The first settlements in the area of Guissona are dated back to the end of the bronze age and the first iron age, near 800bC. They are composed of a little village near a water source, known today as "the fountains" and Vell Pla square.
This first settlers did not knew about writing, they changed from bronze to iron tools and they used to incinerate the dead.
Within late II and early I bC centuries, Iesso becomes a perfectly organized town, with structured streets, a wall protecting the urban area, necropolis and public spaces. It's economy is based on agriculture, although some little pottery and textile workshops were active too.
This ancient city of Iesso is mentioned by documentary roman sources, as Pliny and Ptolomeus.
This city is one of the most important in Catalonia from that period. It was suspected by erudits from the XVI cent. AD, corroborated by archeologic works made in 1933 and proven by further explorations in this last years, new gathered data show the importance of this site and its scientific and historic interest.
Actual investigations make able to take some first interpretation of the urban structure of the city: with a polygonal plant about 18 hectares and a well structured street network, following the typical urban parameters from roman cities from this period.
Conserved elements from the roman Iesso ranges from a huge wall stretch (originally it was 280 meters), one of the entrance doors, and the original Cardo Maximus, with a total length of 560 meters. From the first times of the city one can find the ruins of the termae, two necropolis and a funerary tombstone with versed latin inscriptions.
Roman Iesso occupied a superior extension than the middle age and current city, which make Iesso an exceptional case for roman cities in Catalonia. On the other hand, its influence area was really vast, including the actual La Segarra and some parts of Urgell regions
From VI AD century, and until XI AD, the continuity of the city falls in a black hole, as this is the war period between the arab world and the christian counts and the whole are became a huge no man's land and the frontier between the two worlds.